[LTP] [PATCH v4 2/7] libltpswap: alter tst_count_swaps api

[Yang Xu]

Like we count the ipc resource total, we can also add a
similar api for swapfiles, so we can use it for swapon03 case.

Signed-off-by: Yang Xu <xuyang2018.jy@fujitsu.com>
---
 include/libswap.h         |  5 +++++
 libs/libltpswap/libswap.c | 27 +++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/include/libswap.h b/include/libswap.h
index 361d73175..76a3ed0c0 100644
--- a/include/libswap.h
+++ b/include/libswap.h
@@ -27,4 +27,9 @@ bool is_swap_supported(const char *filename);
  */
 int tst_max_swapfiles(void);
 
+/*
+ * Get the used swapfiles number
+ */
+int tst_count_swaps(void);
+
 #endif /* __LIBSWAP_H__ */
diff --git a/libs/libltpswap/libswap.c b/libs/libltpswap/libswap.c
index a404a4ada..1f9235f17 100644
--- a/libs/libltpswap/libswap.c
+++ b/libs/libltpswap/libswap.c
@@ -265,3 +265,30 @@ int tst_max_swapfiles(void)
 
 	return max_swapfile - swp_migration_num - swp_hwpoison_num - swp_device_num - swp_pte_marker_num;
 }
+
+/*
+ * Get the used swapfiles number
+ */
+int tst_count_swaps(void)
+{
+	FILE *fp;
+	int used = -1;
+	char c;
+
+	fp = fopen("/proc/swaps", "r");
+	if (fp == NULL) {
+		return -1;
+	}
+
+	while ((c = fgetc(fp)) != EOF) {
+		if (c == '\n')
+			used++;
+	}
+
+	fclose(fp);
+	if (used < 0) {
+		tst_brk(TBROK, "can't read /proc/swaps to get used swapfiles resource total");
+	}
+
+	return used;
+}
-- 
2.27.0